Pavement dressing conditioner



July 19,' 1966 E. w. M GOVERN PAVEMENT DRESSING CONDITIONER Filed Aug. 17. 1964 BITUMINOUS PAVEMENT PORTLAND CEMENT CONCRETE .13 GAL. m.

TIME MONTHS INVENTOR. EDWARD W. McGOVERN BY Z w fi W his Z United States Patent 3,261,269 PAVEMENT DRESSING CONDITIONER Edward W. McGovern, Pittsburgh, Pa., assiguor to Koppers Company, Inc., a corporation of Delaware Filed Aug. 17, 1964, Ser. No. 390,022 4 Claims. (CI. 94-23) This invention relates to sealing, reconditioning and dressing bituminous and concrete surfaces.

Bituminous pavings are smooth, confortable to ride upon and easily applied. Unfortunately, the smooth, even surface is not as lasting as would be desired. Bituminous pavements, for example asphalt roads, tend to harden, crack, ravel and generally deteriorate over a period of years until finally the road becomes unsatisfactory for further use. The phenomena is not completely understood. It is believed that the hardening of the asphalt roads may be caused by slow loss of volatile materials from the asphalt and by the oxidation of the asphalt itself. The deterioration proceeds at an increasing rate as the surface of the paving hardens, because it cracks thereby exposing more bituminous surface for oxidation. The cycle repeats; the cracks deepen. Factors such as the penetration of gasoline, kerosene and motor oil dropped from vehicles passing over the surface and also the penetration of water which, in colder climates, causes the pavement to crack due to the freeze-thaw cycle accelerate this deterioration.

Thus arises the need for economically prolonging the useful life of bituminous pavements and the need for economically repairing a badly cracked bituminous pavement.

Concrete surfaces are also subject to deterioration due to the freeze-thaw cycle because water can easily penetrate into the concrete through the small cracks that naturally occur in concrete surfaces. Furthermore, chemicals which are placed on concrete to melt snow and ice accelerate the deterioration.

Seals of coal tar pitch emulsion or asphalt emulsions or slurries as heretofore known have afforded only temporary protection for the pavement surface and have had no beneficial effect on the pavement material as little or no penetration into the paving material occurs. The seals have only capped the substrates.

It has now been found in accordance with the inven tion that bituminous pavements which are in the process of becoming or have become dry and brittle through aging and weathering may be revitalized and protected by applying thereto a composition comprising a mixture of road tar, coal tar solvent having a distillation range of 95 to 250 C. and bituminous pavement rejuvenator whose composition is described in my copending application Serial No. 233,276, filed October 26, 1962, and now Patent No. 3,221,615.

Surprisingly, it has also been found that the composition of the invention will penetrate concrete surfaces. Thus, the composition penetrates and seals the small cracks in the concrete so that solvent, chemicals and water cannot enter even should a break occur in the surface coating. The degree of penetration into the concrete will depend upon the porosity of the concrete.

The drawing illustrates the depth that the composition will penetrate aged bituminous paving and Portland cement concrete pavement with the passage of time.

In the case of bituminous surfaces, the novel pavement dressing conditioner is believed to rejuvenate or prolong 3,261,269 Patented July 19, 1966 ICC the useful life of the bituminous pavements by plasticizing the binder. The novel composition, however, protects both bituminous and concrete surfaces from the deteriorative effects of solvents, chemicals and water by effectively sealing the surface to prevent their penetration into the pavement. The novel composition of this invention is a liquid which can be applied at ambient temperatures (-120 F.), dries quickly and provides rapid and effective penetration into the surface of the pavement. It will also provide water-tight seals for concrete pipe.

The novel composition is preferably applied in the amount of about 0.05 to 0.5 gallon per square yard. Less than 0.05 gallon per square yard seems to be insufficient to adequately seal and rejuvenate the pavement and more than 0.5 gallon per square yard may even cause bituminous pavements to become unstable. Conventional methods of handling liquid bituminous material can be used in applying the composition such as spraying through a bituminous distributor or painting with a brush or roller.

After the novel composition is applied to paving, it is permitted to set for a short period, for example, a half hour. Then, the surface is brushed with a stiff broom to remove any excess composition from low areas and deposit it in the cracks. Thereafter the paving is ready for the movement of rubber tired vehicles thereover. With time, the bituminous pavement rejuvenator plasticizes old bituminous pavement and softens the material in the vicinity of the cracks to the extent that rubber tired traffic will close the cracks. In areas such as airports where the vehicular traffic may be small, it is desirable to roll the rejuvenated bituminous paving with a rubber tired roller.

The novel rejuvenating and sealing composition of this invention continues to penetrate into the surface for a substantial period of time. The extent of penetration may be readily determined visually since the portion which has been penetrated by the novel composition has a color that is darker than that of the original pavement. This penetration is a direct function of the length of time after application. The drawing shows, for example, the depth of penetration in inches of asphalt and concrete paving as a function of time, the determinations having been made by drilling a core from the pavement at various intervals of time.

The extent of plasticizing of the aged bituminous pavement can 'be conveniently illustrated by the use of the characteristic of a bituminous paving material such as penetration. Penetration (ASTM D5-25) is determined by measuring the distance'in tenths of a millimeter that a needle penetrates into the asphalt under controlled conditions. A series of weathered asphalt paving was tested as to penetration after the addition of the novel sealing and rejuvenating composition of this invention to the paving at a rate of .13 gallon per square yard. The results of the tests are illustrated in Table I.

TABLE I Penetration at 77 F. Pavement Number Treated Untreated The novel composition of this invention contains from 50 to 60 percent by Weight of a road tar which is a topped, high temperature coke oven tar (a tar which has had a portion of the lower boiling material removed by distillation) having a float test of 75-220 sec. at 50 C. The float test is a standard test defining the consistency of the road tar with road tar of this consistency being designated as RT-IO, RT-11 and RT-l2.

The composition contains from 20 to 35 percent by Weight of coal tar heavy solvent having a boiling range of 95 to 250 C. The coal tar heavy solvent is made up of light solvent naphtha, a light oil distillation fraction consisting of benzol, toluol, xylol generally designated as B-T-X solvent, and a crude heavy solvent naphtha. The coal tar heavy solvent contains the compounds listed in Table II in the approximate proportions shown.

TABLE II Compounds: Percent by weight Benzol 1-5 Toluol 1-10 Xylol 1-15 Coumarone and indene 20-60 Methyl-coumarone 1-20 Naphthalene 1-15 Ethyl benzene -1 0-, m-, p-Xylene 1-5 n-Heptane, n-octane 0-0.5

n-Propylbenzene, ethyltoluene, trimethylben- Zene 0-3.0

The composition also contains from 15 to 30 percent by weight of bituminous pavement rejuvenator which is described in detail in my copen'ding application Serial No. 233,276, filed October 26, 1962, and now Patent No. 3,221,615.

Briefly the bituminous pavement rejuvenator is a blend of coal tar distillate fractions derived from high temperature coal tar and consists of high boiling, multicyclic aromatic compounds. The blend has a specific gravity at 25/25 C. of at least 1.08 and an initial boiling point of at least 180 C., a continuous boiling range to at least 300 C. with 70-40% of the material remaining as residue at 300 C. with a distillation curve to 300 C. of

Temperature, C.: Distillate 180 max 1.0 190 maX 2.0 200 max 3.0 210 max 4.0 220 max 5.0 230 max 6.0 240 max 10.0 250 2-18 260 5-30 270 -40 280 -45 290 -55 300 -60 and said distill-ate to 300 C. having a minimum specific gravity at 25/25 C. of about 1.025. The aromatic compounds are *di-, triand tetracyclic hydrocarbons and their derivatives including a significant amount (from about 1 to 10%) of phenolic and hydroxy derivatives. The composition contains resinous materials which are the multicycl-ic condensation products of the di-, triand tetracyclic compounds formed When the compounds are subjected to high temperature distillation.

While the bituminous pavement rej uvenator may contain many aromatic compounds which boil above 180 C. the major components that a typical blend contains are listed in Table III along with the desired ranges in percent by weight in which each component should be present.

4 TABLE III Major components of bituminous pavement rejuvenator Compounds: Percent by Weight Naphthalene 1-5 a-Methylnaphthalene 1-10 fi-Methylnaphthalene 1-15 Dimethylnaphthalene 1-20 Acenaphthene 1-10 Fluorene 2-20 Phenanthrene 2-20 Anthracene 2-10 Carbazole 1-5 Fluoranthene 1-5 Pyrene 1-5 Crysene 1-5 Tar acids 1-10 Tar bases 1-15 Resinous compounds 1-10 The bituminous pavement rejuvenator includes a larger percentage of aromatic compounds having high solvent powers (e.g., alkyl-naphthalenes) than are normally found in a simple coal tar distillate having the same general boiling range. These solvent compounds are particularly compatible with the bituminous pavement materials and this gives the rej uvenator its excellent penetrating and plasticizing properties. At the same time the solvents prevent any crystals from forming in the rejuvenator due to supersaturation of the solutions with any of its components.

The presence of the tar acids (phenolic and hydroxyl derivatives) acts to plasticize the brittle oxidized asphalt by dissolving the oxidation products therein. These tar acids include for example xylenols, naphthols, p-phenyl phenol, hydroxyphenanthrene, etc.

A typical pavement dressing conditioner of this invention can be prepared by mixing the components in a conventional mixing tank in the manner of Example I.

EXAMPLE I Topped coke oven tar (-100 seconds Float Test at 50 C., 52.4 parts by weight) at a temperature of 180 F. was added to a mixing tank equipped with a three-bladed impeller. To the tank were then added, at ambient temperature, 11.6 percent by Weight of B-T-X solvent and 20 percent by weight of cnude heavy solvent naphtha (containing 50 percent resinifiable coumarone-indene resin). The mixture was stirred at 60 rpm. for 15 minutes and then 16.0 percent by weight of bituminous pavement rejuvenator at a temperature of 150 F. was added. The mixture was stirred for an additional minutes to thoroughly mix the ingredients. The pavement dressing conditioner Was then transferred to a storage tank at ambient temperature.

The specifications for the sealing, dressing and rejuvenating compositions of this invention are as follows:

It is believed that if it were possible to segregate the action of the components that the tar portion of the novel composition provides a solvent and water-tight seal for the substrate, while the bituminous pavement rejuvenator portion revitalizes the aged bituminous paving substrate by replacing volatile materials and by plasticizing the binder thereby preventing further cracking of the pavement and healing existing cracks and fissures. The solvent portion not only provides a compatible vehicle for the other two components but, more importantly, permits the composition to be applied at ambient temperatures (60-120 F.) and promotes rapid penetration of the composition into the substrate. The solvent portion also promotes a drying of the surface. These actions occur conjointly and the action of one mutually atfects the action of the other so that separation of the effects is not possible.

The composition can be mixed with sand, pozzolana or other fine mineral aggregates prior to application where, due to heavy trafiic, a coating having more body is desired.

In treating bituminous and concrete paving, the composition is applied to the paving advantageously by spraying at a rate, for example, of 0.1 gallon per square yard. The composition is permitted to soak for minutes to one-half hour and thereafter distributed further over the surface and into the cracks by brushing with a stiff broom. The drying time of the material will vary between 30 minutes to 12 hours depending upon the type of pavement, condition of the pavement and climatic conditions. When traffic is to proceed immediately over the paving, it is desirable to sprinkle the paving with sand so as to minimize pickup of the rejuvenating composition on the tires of the cars. The composition effectively seals concrete and bituminous surfaces against fuel, oil, water and ice removing chemicals.

If the traflic is not heavy, it is advantageous to roll bituminous paving at the end of 60 days with a roller having rubber tires. The rejuvenator restores the cold flow properties of bituminous pavement and its flexibility so that it behaves in the manner of a new pavement.

The composition can be used to rejuvenate old bituminous pavements and seal them against further deterioration as well as sealing bituminous or concrete surfaces which have not begun to deteriorate but due to age, use or climatic conditions will be suspected to soon deteriorate unless an effective sealing compound is applied.

In the sealing of the surface of concrete pipe the composition can be applied to either the inner or outer surfaces of the pipe by sprayer, brush or roller. A satisfactory rate of application would be, for example, 0.1 gallon per square yard. The composition prevents the seepage of liquids through the pipe wall and thus provides an effectively sealed conduit. It also prevents the passage of moisture into the pipe wall, which, in cold climates would freeze and crack the pipe.

The foregoing has presented novel compositions and methods of rejuvenating asphalt pavements, sealing and dressing asphalt and concrete pavements and providing a water-tight seal for porous material such as concrete pipe. It is particularly advantageous for use on airport runways, taxiways and parking strips to rejuvenate old bituminous pavements and to provide an effective seal against the effects of gasoline, JP-4 jet fuel and motor oil. It is also advantageous for use on city streets where decreasing curb heights inhibit the use of additional pavement overlays unless new curbs are placed or unless the present pavement is removed to some depth in order to provide effective drainage. It is also advantageous for use on concrete pavements where in cold climates the effect of penetration by water and the resulting freezethaw cycles and the placing of ice and snow removal chemicals on the surface causes rapid deterioration unless some protective layer is applied. The composition can be applied at ambient temperatures which eliminates the necessity for heating the composition prior to application with its attendant unfavorable economic aspect and problems due to fumes which can have adverse eifects on the personnel applying the coating. The solvent system provides a quick drying surface and permits the rejuvenating and sealing compound to rapidly penetrate the pavement to an effective depth.

Other applications of the novel composition include the pretreatment of cracked pavements prior to overlaying with new bituminous courses so that the cracks in the old pavement will not be reflected up to the new overlay. It can be used to pretreat pavement surfaces after planing operations with a conventional heater planer or to pretreat pavement prior to heating with conventional infrared equipment used for healing cracks.

I claim:

1. A sealing and rejuvenating composition for bituminous and concrete surfaces comprising 50-60% by weight of topped coke oven tar having a float test of 75-220 sec. at 50 C., 20-35% by weight coal tar solvent having a boiling range of -250 C. and 15-30% by weight of a mixture of di-, triand tetracyclic aromatic compounds and their alkyl homologs containing lower alkyl groups together with 110% by weight of phenolic and hydroxy derivatives, said mixture being derived from the distillation of coal tar, said mixture having a specific gravity at 25/25 C. of at least 1.08 and an initial boiling point of at least C., a continuous boiling range to at least 300 C., 70-40% of the material remaining as residue at 300 C., with a distillation curve to 300 C. of

and said distillate to 300 C. having a minimum specific gravity at 25/25 C. of about 1.025.

2. A method of sealing and rejuvenating bituminous and concrete surfaces which comprises applying to the surface at a rate of 005-05 gallon per square yard to composition comprising from 50-60% by weight topped coke oven tar having a float test of 7 5-220 seconds at 50 C., 20-35% by weight coal tar solvent having a boiling range of 95250 C. and 1530% by weight of a mixture of di-, triand tetracyclic aromatic compounds and their alkyl homologs containing lower alkyl groups together with 1-10% by weight of phenolic and: hydroxy derivatives, said mixture derived from the distillation of coal tar, said mixture having a specific gravity at 25/25 C. of at least 1.08 and an initial boiling point of at least 180 C., a continuous boiling range to at least 300 C., 70-40% of the material remaining as residue at 300 C. with a distillation curve to 300 C. of

7 and said distillate to 300 C. having a minimum specific gravity at 25/25 C. of about 1.025, so that said composition will penetrate and seal said surface.

3. A sealing and rejuvenating composition for bituminous and concrete surfaces comprising from 50-60% by weight of topped coke oven tar having a float test of 75- 220 seconds at 50 C., from 20-35% by weight of a first mixture of light solvent naphtha and benzoltoluolxylol solvent having a boiling range of 95-200 C. and crude heavy solvent naphtha having a boiling range of 120-250 C. and from 15-30% by weight of a second mixture of di-, triand tetracyclic aromatic compounds and their alkyl homologs containing lower alkyl groups together with from 1-10% of phenolic and hydroxy derivatives, said second mixture being derived from the distillation of high temperature coal tar, said second mixture having a specific gravity at 25/25 C. of at least 1.08 and an initial boiling point of at least 180 C., a continuous boiling range to at least 300 C., 40-70% of the material remaining as residue at 300 -C. with a distillation curve to 300 C. of

Temperature, C.: Distillate 180 max 1.0 190 max 2.0 200 max 3.0 210 max 4.0

220 max 5.0 230 max 6.0 240 max 10.0

and said distillation to 300 C. having a minimum specific gravity at 25/25 C. of about 1.025, such that said sealing and rejuvenating composition has a minimum specific gravity at 25/25 C. of about 1.06.

4. A method of sealing and rejuvenating bituminous and concrete surfaces which comprises applying to the surface at a rate of 0.050.5 gallon per square yard a composition from 60% by Weight of topped coke oven tar having a float test of -220 seconds at 50 C.,

8 from 2035% by weight of a first mixture of light solvent naphtha and benzol-toluol-xylol solvent having a boiling range of -200 C. and crude heavy solvent naphtha having a boiling range of -250 C. and from 15-30% by weight of a mixture of d-i-, triand tetracyclic aromatic compounds and their alkyl homologs containing lower alkyl groups together with from 110% by Weight of phenolic and hydroxy derivatives, said mixture being derived from the distillation of high temperature coal tar, said second mixture having a specific gravity at 25/25 C. of at least 1.08 and an initial boiling point of at least C., a continuous boiling range to at least 300 C., 40-70% of the material remaining as residue at 300 C. with a distillation curve to 300 C. of

Temperature, C.: Distillate 180 max 1.0 rnax 2.0 200 max 3.0 210 rnax 4.0

220 max 5.0

230 max 6.0

240 max 10.0

and said distillation to 300 C. having a minimum specific gravity at 25/25 C. of about 1.025, such that said sealing and rejuvenating composition has a minimum specific gravity at 25/25 C. of 1.06.

References Cited by the Examiner UNITED STATES PATENTS 2,639,651 5/1953 Scott 9423 2,701,213 2/1955 Neville 106-278 2,937,950 5/1960 Tillman 106285 2,983,666 5/1961 Stowe 20842 3,221,615 12/1965 McGovern 9423 JACOB L. NACKENOFF, Primary Examiner. 

2. A METHOD OF SEALING AND REJUVENATING BITUMINOUS AND CONCRETE SURFACES WHICH COMPRISES APPLYING TO THE SURFACE AT A RATE OF 0.05-0.5 GALLON PER SQUARE YARD TO COMPOSITION COMPRISING FROM 50-60% BY WEIGHT TOPPED COKE OVEN TAR HAVING A FLOAT TEST OF 75-220 SECONDS AT 50* C., 20-35% BY WEIGHT COAL TAR SOLVENT HAVING A BOILING RANGE OF 95-250*C. AND 15-30% BY WEIGHT OF A MIXTURE OF DI-, TRI- AND TETRACYCLIC AROMATIC COMPOUNDS AND THEIR ALKYL HOMOLOGS CONTAINING LOWER ALKYL GROUPS TOGETHER WITH 1-10% BY WEIGHT OF PHENOLIC AND HYDROXY DERIVATIVES, SAID MIXTURE DERIVED FROM THE DISTILLATION OF COAL TAR, SAID MIXTURE HAVING A SPECIFIC GRAVITY AT 25/25*C. OF AT LEAST 1.08 AND AN INITIAL BOILING POINT OF AT LEAST 180*C., A CONTINUOUS BOILING RANGE TO AT LEAST 300*C., 70-40% OF THE MATERIAL REMAINING AS RESIDUE AT 300*C. WITH A DISTILLATION CURVE TO 300*C. OF TEMPERATURE, *C.: DISTILLATE 180 MAX 1.0 190 MAX 2.0 200 MAX 3.0 210 MAX 4.0 220 MAX 5.0 230 MAX 6.0 240 MAX 10.0 250 2-18 260 5-30 270 15-40 280 20-45 290 25-55 300 30-60 AND SAID DISTILLATE TO 300*C. HAVING A MINIMUM SPECIFIC GRAVITY AT 25/25*C. OF ABOUT 1.025, SO THAT SAID COMPOSIRION WILL PENETRATE AND SEAL SAID SURFACE. 